Method of riveting wood and metal elements



Nova 14, 1933. A. s. VAN HALTEREN METHOD OF RIVETING WOOD AND METAL ELEMENTS Filed April 14, 1.930

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4.1 1 l1 3 1 a 0 a Patented Nov. 14, 1933 PATENT OFFICE METHOD OF RIVETING WOOD AND METAL ELEMENTS Andrew S. Van Halteren, East Lansing, Mich., assignor to Motor Wheel Corporation, Lansing, Mich., a corporation of Michigan Application April 14, 1930. Serial No. 443,941

2 Claims.

In permanently assembling articles which comprise composite elements such' as a wood layer between layers of metal, as by means of rivets, difliculties are presented which it is the primary object of my invention to overcome.

If the rivets are headed cold, there is a tendency of the rivet shank to swell or buckle within the wood under the heavy end pressure required to upset the rivet as by blows of a riveting hammer;

whereas if the rivets be heated to facilitate upsetting, there is a burning of the wood and a consequent loose fit about the rivet shank within the wood.

I solve these difliculties by heating the end of the rivet locally to a temperature permitting of easy upsetting while maintaining the shank of the rivet in contact with the wood suficiently cool to avoid any burning effect.

This local heating of the rivet end may be accomplished in'divers ways, of which exemplifications may be given as follows:

Forming the rivet end with a reduced section of metal by coring the same axially, or reducing the outside diameter, or providing an annular external groove, and then applying one electrode to the head of the rivet and another upsetting electrode to the end of the rivet, the portion of reduced section only will be heated to any substantial extent.

Again, a rivet of uniform or non-uniform section may be used, and the electrodes applied one to the metal plate adjacent that end of the rivet to be upset and the other pressure electrode to the rivet end.

In either case, the swelling of the upset end of the rivet into intimate contact with the metal plate at that end will cause a rapid dissipation of the heat and a quick cooling.

Added advantages are presented in my improved method inasmuch as the metal is tempered by rapid cooling of the upset end; there is no fracturing of the metal particles of the rivet head as is possible where cold riveting is practiced; and no great pressure is required to upset the heated rivet as in the case of blows required in cold riveting.

In order that the invention may be readily understood by those skilled in the art, a diagrammatic representation of the conditions employed and steps practiced is presented in the accompanying drawing as applied to the permanent securing of the metal and wood parts in a wood wheel hub assembly, by way of example.

In the drawing:

Fig. 1 is a conventional illustration of a fragmentary radial section of a wood wheel hub assembly;

Figs. 2, 3, 4 and 5 are fragmentary sections illustrating the rivet in place ready for upsetting;

Figs. 6, 7 and 8 are schematic plan views illustrating the relation between the end of the rivet and a metal plate prior to upsetting; and

Figs. 9, 10 and 11 represent, respectively, two forms of rivets and their relation to the metal plate.

Referring to the drawing in detail, by way of example, a wheel hub is indicated at 11 comprising the hub barrel 12 and permanent hub flange 13. Between the flange 13 and the brake drum 14 is disposed the wheel spider comprising wood spokes 15. One of a series of rivets having shanks 16, original heads 17 and an upset head 18 is shown as permanently binding the spoke 15 between the hub fiange 13 and the brake drum 14.

It will be obvious that if the rivets 16 are inserted hot, the wood of the spoke 15 will be charred where it contacts with the heated shank of the rivet. It will also be evident to those skilled in the art that if a cold rivet 16 were employed and headed cold, the heavy pressure blows required to upset the rivet will tend to cause a swelling or buckling of the shank where it transfixes the wood element.

In order to accomplish the hot upsetting of the rivet without injuriously afiecting the wood element of the assembly, any one of a number of expedients may be adopted, all of which are embraced within my invention, several of which expedients are illustrated in the other figures of the drawing.

According to Fig. 2, an anvil electrode 19 forms one terminal of an electric circuit indicated at 20 while a pressure electrode 21 forms the other terminal of the electric circuit as indicated at 20*. In this case, the rivet is provided with a cored end portion 16 of reduced metallic cross section which fits within an aperture of the brake drum 14.

The anvil electrode 19 is brought into supporting contact with the rivet head and the pressure electrode is brought into pressure contact with the reduced end of the rivet; When the electric circuit is closed, the passage of the electric current through the rivet will cause a rapid heating of its reduced ,end, by reason of the greater resistance, while the shank of the rivet will remain substantially unheated. The pressure of the electrode 21 will cause an upsetting of the reduced rivet end, substantially closing of its central cavity, thus forming a conventional rivet head as indicated at 18 in Fig. 1. The heating and upsetting of the rivet is practically instantaneous, and likewise the dissipation of the heat through the metal plate 14.

In Fig. 3 the method is substantially the same, the only difference being that the reduction or cross section in the rivet end is obtained by providing the same with an external annulargroove 16 The same method of procedure applies to Fig. 4, the only diflerence residing in efiecting a reduced cross section of the rivet end by decreasing its over-all diameter as represented at 16.

According to Fig. 5, the anvil 19 does not serve as an electrode but purely as a support for the head 17 of the rivet 16. Herein the metal plate 14 of the brake drum forms one terminal 20 of the electric circuit while the pressure electrode 21 forms the other terminal of the electric circuit as indicated at 20. In this instance, the rivet end is shown as having an intimate contact with the plate 14 of the brake drum, such contact, amounting to a driving fit, being obtained, as illustrated in this figure, by slightly tapering the rivet end, as indicated at 16 The rivet 16 being sup ported by the anvil 19 and the pressure electrode 21 being brought into pressure relationship to the rivet end, the closing of the circuit will cause a flow of electric current through the plate 14, the rivet end 16 and the pressure electrode 21, the shank of the rivet 16 not being included in the circuit and consequently being unheated to any degree. Here, as in the other examples given, the rivet end will be instantly heated and upset when the circuit is closed and pressure applied and the same rapid cooling will be effected by dissipation of the heat through the plate 14.

It will be appreciated that, under the method last described, it is important that there be an intimate electrical contact between the plate 14 and the rivet adjacent the end to be upset. Where this condition is attained by tapering the rivet end and driving the same into the aperture 14 provided in the plate 14, there may persist a slight clearance about the rivet at the outer face of the plate as indicated in Fig. 6, into which clearance space the heated metal of the rivet is displaced by the heating operation.

An intimate contact between the plate 14 and the rivet end 16, according to the method illustrated in Fig. 5, may be obtained by providing the plate 14 with a polygonal aperture 14 into which the end of the rivet 16 may be driven as indicated in Fig. 7.

A close contact between the plate 14 and the end of a standard rivet 18 is also obtainable in practice by employing a polygonal punch and a round die for producing the rivet-receiving apertures in the plate, the result being an aperture round on the die side and polygonal on the punch side. Such an aperture in relation to the end or the rivet 16 is represented at 14 in Fig. 8.

Even better results have been found to follow the employment of a rivet having that portion of its shank adjacent its end formed of polygonal cross-section as indicated at 16 and 16 in Figs. 9 and 10 and then driven into a round aperture 14 as indicated in Fig. 11. The spur corners oi the polygonal portion of the rivet shank bite into the metal oi. the plate, thus insuring a good electrical contact between the rivet and plate as indicated in Fig. 11.

I claim:

1. The method of riveting metal members together upon an interposed wood member which comprises providing the members with aligned apertures, forming a rivet with a head and with a generally cylindrical shank of a diameter closely fitting said apertures and that end portion opposite its head with lateral spurs having an over all diameter greater than the cylindrical portion of the shank, transfixing the apertured members with such rivet with the head seated against one of the metal members and the spurred portion engaged within the aperture oi. the other metal member with its end projecting, applying one terminal of an electric circuit to that metal member adjacent the rivet end and the other terminal to the projecting end of the rivet whereby to heat that end of the rivet locally, and finally exerting pressure by the second terminal to upset the heated end of the rivet.

2. The method of electrically riveting through metal which consists in deforming the rivet shank circumferentially adjacent its end to form thereon radially projecting ridges, driving the rivet into an aperture of the metal to force the ridges into the metal wall of the aperture, applying one electrode to the metal and a second electrode to the rivet end, applying electric current to heat the rivet between the metal and the rivet end, and applying pressure by means of the second electrode whereby to upset the heated rivet end.

ANDREW S. VAN HALTEREN; 

